This invention relates to nuclear reactors and has particular relationship to such reactors including a thermal insulating shield. A nuclear reactor, particularly of the pressurized light-water type, has a pressure vessel including a generally cylindrical body and a dome-shaped head. The head is removable for refueling and other services. To conserve the thermal energy developed in the reactor, it is provided with a thermal shield. The shield extends about the body and over the entire closure head. Part of the shield that covers the top of the head is removable as part of the head. Other parts of the shield for the head must be removed to afford access to unscrew the studs to remove the head.
In accordance with the teachings of the prior art, the thermal insulation on the head includes a plurality of mating pads which extend over at least a portion of its outer surface. When the head is to be removed, the pads are separately removed from the head. The removal is effected manually usually by lifting the pads one-by-one from the head. This process is time consuming and requires that personnel be exposed to radiation.
It is an object of this invention to overcome the drawbacks and disadvantages of the prior art and to provide thermal insulation for the head of a nuclear reactor which shall be readily removable by remote control, without exposure of personnel to radiation, to permit removal or replacement of the head.